Quick-firing corona regulator tube



May 7, 1957 H. F i QIEDMAN QUICK-FIRING ,(Z/ORONA REGULATOR TUBE FiledNov. 24, 1954 720 730 740 VOLTAGE APPLIED ILE-E UNREGULATED HIGH VOLTAGEII OUTPUT ll l INVENTOR HERBERT FRIEDMAN ATTORNEYJ sen I United StatesPatent QUICK-FIRING CORONA REGULATOR TUBE Herbert Friedman, Arlington,Va.

Application November 24, 1954, Serial No. 471,138

3 Claims. (Cl. 313197) (Granted under Title 35, U. 5. Code (1952), see.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

The present invention relates to a quick-firing corona regulator tubeand is particularly an improvement over my Patent No. 2,523,287 forVoltage Regulator.

In the art of corona voltage regulation by means of a diode typeregulator tube of the character disclosed in my above identified patent,there exists a statistical delay in the initiation of a corona dischargefollowing the application of an overvoltage to the tube. This delaycomes about by virtue of the fact that the initiation of the coronadischarge depends upon the occurrence of a fortuitous external ionizingevent. As a consequence, the corona firing or starting voltage isunreliable. In certain applications where delicate instruments rely onthe voltage output for the regulator, this initial overvoltage mayobtain magnitudes which are detrimental to the life or even instantlydestructive of the instruments.

The present invention overcomes the foregoing shortcomings by providingthe regulator tube with a simple, convenient, self-contained ionizingmechanism. Specifically, the instant invention includes the addition ofan auxiliary electrode disposed Within the tube and structurallyproportioned and positioned relative to the main cathode so as toundergo a discharge at applied voltages below that for which mainelectrode structure operates. The auxiliary electrode dischargeoperates, as hereinafter described, to provide an ionizing effect on theelectrode structure to minimize the delay time in the tube and thus tostabilize the corona starting voltage for the tube. The provision of anauxiliary electrode in the tube not only is a simple and convenient wayof overcoming the aforementioned shortcomings but also has manyadvantages over other prior tubes that required radio-active material toexcite the gas and cause ionization. The tube of the present inventioncan be made much cheaper, does not require special handling duringmanufacture and use to avoid contamination due to radio-activeradiation, can be disposed of readily, and does not require theexpensive materials required in the other tubes.

It is accordingly an object of the present invention to provide asimple, reliable correction for the foregoing shortcomings in coronaregulator tubes.

A further object of this invention is to provide a simple, inexpensivecorona regulator tube having stabilized starting voltage properties.

A still further object of this invention is to provide a coronaregulator tube having the foregoing advantages and yet which is safe tohandle at all times without danger of contamination from radiation.

Other and more specific objects of this invention will become apparentupon a careful consideration of the following detailed description whentaken together with the accompanying drawings, in which:

Fig. l is a simplified elevational view of an exemplary embodiment ofthe invention,

- gas within the cathode cylinder.

Fig. 2 illustrates, in circuit form, a type of circuit useable inpracticing the teaching of this invention, and

Fig. 3 shows a graph illustrating the applied voltage Vs the growth ofcorona discharge in the tube.

Referring now to Fig. 1 there is illustrated a side elevational view ofone typical embodiment of the regulator tube 10 comprising thisinvention. As exemplified, the tube may comprise a vessel or envelope 14made of any desired material, such as glass, in which three electrodesare disposed. These electrodes include a cathode cylinder 11 made fromany suitable metal such as stainless steel, copper, et-c., held inposition by a support 21 through the side of the envelope 14 which has areinforced portion 22 on the side thereof. The support 21 also affordsan electrical connection for the cathode 11. An inner coaxial anodecylinder 12, also made of any suitable material and having the sameratio of radius relationship to the cathode cylinder as disclosed inPatent No. 2,523,287, and a corona stabilizing auxiliary electrode 13illustrated as being disposed externally of the cathode cylinder 11. Theauxiliary electrode 13, which may assume various shapes, may also bemade of any desirable metal and may be placed within the cathodecylinder instead of externally thereof, if desired. In the illustratedembodiment, the electrode 13 consists of a fine wire spaced externallyof and near the cathode cylinder. In a typical tube the electrode 13 maybe approximately /3 the diameter of the anode and spaced a distance fromthe cathode equal to approximately /3 the anode distance from thecathode surface. As indicated by the above dimensions, the radius ofcurvature of the wire electrode 13 and/or its spacing relative to themain cathode 11 is chosen so that when electrode 13 is electricallyparalleled with the main anode by a suitable resistance R2 as shown inFig. 2, a corona discharge between electrode 13 and cathode 11 will takeplace at a voltage below that required to initiate a corona dis-- chargebetween the main electrodes 11 and 12. The cathode cylinder ispreferably equipped with an aperture 16, or a slit, or some form of anopening therein located adjacent the electrode 13 so that theultraviolet light produced by the corona discharge between electrode 13and the cathode can shine through the opening to cause photoelectricemission from the cathode to ionize the Although it is not necessarythat there be an opening through the cathode cylinder, it is a preferredarrangement when the electrode 13 is external of the cathode cylinder.

As indicated, the three electrodes are preferably enclosed within a gastight vessel or envelope, which in turn is filled to a predeterminedpressure with any suitable gas such as helium, neon, mixtures of raregases with hydrogen, etc., as disclosed in Patent No. 2,523,287. Theelectrodes are connected to terminal pins which are well known in theart.

In the circuit illustrated in Fig. 2, the positive or unregulated highvoltage (+H. V.) is applied to the circuit as shown and the regulatedvoltage is obtained from across the main electrodes 12 and 11 of thetube. The circuit resistance R1 connected in series with the anode 12provides the necessary voltage dropping resistance in the typicalregulator fashion. Resistance R2 connected in the circuit before theresistance R1 as shown at A and in series with the electrode 13, oralternatively the resistance R2 can be connected between the resistanceR1 and the anode as indicated at B operates to electrically isolate theauxiliary electrode from the main discharge path.

Fig. 3 shows in graphical form the manner in which the corona dischargecurrent for the main electrodes of the tube varies with applied voltage.The discharge portion above vmin is known as the region of stable coronadischarge. Specifically, this region is defined as that portion of thevoltage-current characteristic where a selfsustaining discharge occurs.The region between Vs and vmin is known as the unstable corona region.When the positive high voltage is applied, the tubes of the typedisclosed in my above identified patent have a tendency to fire at anypoint above Vmin in the stablecorona region, the specific pointdepending upon the occurrence ofa fortuitous, external ionizing event.The object of this invention is to stabilize the firing level at a pointnear Vs- In the prior tube, at voltages lower than Vmin the discharge isnot self-sustaining and breaks ofi after a mean lifetime that approacheszero, as the applied voltage approaches Vs. If ionizing radiation issupplied from an external source, or if the cathode is illuminated byultraviolet light the initiation of corona can be stabilized down to V5.Below Vs no corona discharge is possible. Thus when the dischargeelectrode 13 which is proportioned and positioned relative to cathode 12to undergo a stable corona discharge at a voltage below Vs fires, theattendant ultraviolet light shines on the cathode, and ionizingradiation is supplied to the main electrode structure. The thresholdvoltage for the establishment of stabilized corona in the auxiliarydischarge is, as hereinabove mentioned, set at a value slightly belowthe thres-. hold V for unstable corona in the main discharge. The exactvoltage level at which stable corona is made to occur in the auxiliarydischarge is thought to be immaterial so long as the ultraviolet lightproduced by the auxiliary electrode 13 shines on the cathode ionizingthe gas within the tube and thereby allowing the main electrodes to firein a stabilized corona discharge region without any delay.

Obviously many modifications and variations of the present invention arepossible in the light of the above teaching. It is therefore to beunderstood, that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. In a corona voltage regulator tube comprising a gas filling, a hollowcylindrical cathode, a wire anode disposed centrally along and in saidcathode, the improvement which comprises an auxiliary fine wire anodehaving a diameter substantially less than that of said anode in saidcathode, said auxiliary fine wire anode being so spaced from andarranged in respect to said cathode as to undergo corona discharge atvoltages below the corona discharge potential of the wire anode in saidcathode.

2. In a corona voltage regulator tube comprising a gas filling, a hollowcylindrical cathode, a wire anode disposed centrally along and in saidcathode, the improvement which comprises an aperture in the wall of saidcathode, an auxiliary fine wire anode externally of said cathode andhaving a diameter substantially less than that of said anode in saidcathode, said auxiliary fine wire anode having a portion thereof lyingwithin the zone opposite said aperture in the wall of said cathode andso spaced from and arranged in respect to said cathode as to undergocorona discharge at voltages below the corona discharge potential of thewire anode in said cathode.

3. In a corona voltage regulator tube comprising a gas filling, a hollowcylindrical cathode, a wire anode disposed centrally along and in saidcathode, the improvement which comprises an aperture in the wall of saidcathode, an auxiliary fine wire anode externally of said cathode andhaving a diameter equal to about onethird the diameter of said anode insaid cathode, said auxiliary fine wire anode having a portion thereoflying within the zone opposite said aperture in the wall of said cathodeand so spaced from and arranged in respect to said cathode as to undergocorona discharge at voltages below the corona discharge potential of thewire anode in said cathode.

References Cited in the file of this patent UNITED STATES PATENTS1,878,341

